Speakers are a well-known component used in many types of electronic devices, such as televisions, radios, telephones, video games, computers, alarm clocks, automobiles, and even calculators. Many of these products contain electronic components or assemblies that emit unwanted electromagnetic or radio frequency signals. In other cases, the electronic components themselves are susceptible to interference by these signals, thereby degrading the performance of the device. This phenomenon is known collectively as EMI or RFI interference and is well known in the art. Radios and computers, have a great need to shield the interior components and the user from undesirable radiation.
This transmission of radiation into and out of radio and cellular telephone housings poses a problem for radio performance and compliance to federal regulations. While many techniques exist for providing shielding of the housing, the problem of shielding the housing openings required to accommodate speakers in these devices continues to exist.
Numerous schemes have been invoked, such as placing metal mesh or screen over the openings, or using metallized felt, in order to shield the openings from EMI and RFI. However, these approaches suffer from the disadvantage of requiring extra materials and labor to fasten the screen or shield in place in the housing and to make it electrically connected to the housing. Typically, the Shields are glued or welded into place, and this is an expensive and cumbersome secondary operation. The speaker opening is typically hard to shield because the opening must be acoustically transparent. Sometimes the speaker is located outside of the shielded area, requiring additional space in the product. A method of providing an EMI/RFI shielded speaker would be highly desirable and a welcome addition to the art.